THE INTELLECTUAL OBSERVER 



JUNE, 1869. 



LIFE CHANGES ON THE GLOBE. 



BY HENRY J. SLACK, F.G.S. 



An assemblage of facts concerning any branch of Nature's 

 operations cannot fail to interest an intelligent being ; but they 

 do not constitute a science until they are arranged and co- 

 ordinated, so as to mark the ascent from particular, to general, 

 or universal truths, and thus contribute to that speculative phi- 

 losophy which constitutes the noblest triumph which the human 

 intellect can achieve. Regarded in this light, departments of 

 physical inquiry are interesting in proportion to the amplitude 

 of the views which they disclose, or in other words in propor- 

 tion to the number and variety of special facts which they are 

 able to refer to simple principles, or comprehensive laws. Mo- 

 dern discoveries concerning the correlation and conservation of 

 forces show us the purely artificial character of the divisions 

 which the limitation of our faculties compels us to make, and 

 point to the conclusion that all spheres of activity, all realms of 

 space would only exhibit the phenomena of a single science to a 

 mind capable of grasping the majestic whole. In the direction 

 of this goal, man, as the child of Time and the heir of Immor- 

 tality, feels that he is progressing. It may be, probably must 

 be, for ever afar off, and impossible to attain, but when we 

 deal with infinities, an approach may be constant, a boundary 

 never reached. 



Among the sciences which at the present time exercise the 

 profoundest influence upon the diligent searcher, and the casual 

 collector of the golden particles of truth, geology must claim 

 a noble rank, and although — dating its progress in time — it is 

 one of the shortest of the many rivers of knowledge, it has 

 become one of the broadest and richest through the confluence 

 of a thousand tributary streams. At a very early period of its 

 brief career, it connected the changes in the structure of the 

 globe, with successive scenes of animated life, and extended 

 the domains of what is commonly called ' ' natural history," and 

 other biological sciences, from the limited present to the im- 

 70L. i. — no. v. z 



